Secondhand Cannabis Smoke and Children

If you smoke cannabis (marijuana) and have children, don’t smoke it in the house. As with tobacco smoke, secondhand cannabis smoke can be absorbed by children of smokers, according to a study in Pediatrics in December 2018. The study was done in Colorado, where recreational use of cannabis is legal.

Researchers found that nearly half of 83 children (average age six) whose parents smoked cannabis had detectable levels of cannabis byproducts in their urine, including 11 percent with THC (tetrahydrocannabinol), the main psychoactive ingredient.

Research on the health consequences of cannabis smoking has been limited and has produced inconsistent results, but there have been even fewer studies on secondhand cannabis smoke. The smoke contains potentially toxic and carcinogenic chemicals, such as volatile organic compounds, polycyclic aromatic hydrocarbons, and aromatic amines.

Studies in adults have shown that inhaling intense secondhand cannabis smoke can have effects similar to smoking marijuana, and animal studies have found that even brief exposure to secondhand cannabis smoke can impair blood vessel function, as was discussed in the new study.